US 2850337 A
Description (OCR text may contain errors)
N. C. MCCALLUM BEARINGS 2 Sheets-Sheet l Filed March 25, 1955 2 a oh 40 m 9 w f5 Z w J e 2 M. 3 4 2 J n A. .s ruw/H 3 92 4 2 ,D 3 4 7l f .M zu w 7% Sept- 2, 1958 N. c. MGCALLUM 2,850,337
BEARINGS Filed March 25, 1955 V2 Sheets-Sheet 2 y 29 f 47 ze l l 27 l United BEARBGS Neviile Clyde McCallum, Perth, Western Australia,
f Australia This invention has reference to improvements in and relating to bearings, particularly that type generally termed encased fluid pressure bearings.
This type of bearing is commonly used on agricultural machinery, such as for the mounting of the discs on disc ploughs, and is consequently subjected to high endwise, i. e. longitudinal, shock factors. Hitherto, bearings which have been used for this purpose have a short life before being fractured as a result of these forces.
It is an object of the present invention to overcome such disadvantage and increase the life of this type of bearing by producing such improvements in this class of bearing, which will perform elhciently and effectively, and which will also be adapted to be readily manufactured, and easily assembled.
Furthermore, this type of bearing, for eicient lubrication particularly when using grease, should be lled with lubricant. At present however, when they become warm, the said bearings suffer from the disadvantage, through the lubricant expanding, of the bursting of the seals, and at times, even the bearing itself. A further object therefore, is to produce a bearing which is not sub- Jiect to this disadvantage.
By the herein invention, l set forth one form of a bearing and associated members, and its `application to the invention in general, such bearing for example being usable in conjunction with agricultural implements. It will of course be understood however, that the invention is not limited to such types of machines, but may be used and applied to machinery in general.
With this and other objects in view which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:
Figure l is a sectional elevation of the bearing;
Fig. 2 is a plan view, partly in section of the bearing showing in Fig. l;
Fig. 3 is a fragmentary sectional elevation, .showing the association of a ball race;
Fig. 4 is a sectional elevation, on an enlarged scale of a variable pressure relief valve.
Referring to the said drawings:
Within the main body or casing lll of the bearing, is housed companion roller bearing or races 11-12. One of these as ll is subjected to pressure from a spiral spring i3, whilst its companion as l2 is held captive by a suitable collar or shoulder as le. One purpose of ,this spring is to render the whole bearing self-adjusting, but in this type of bearing, particularly when used in agricultural impiements, such as stump-jump disc ploughs, or any other machine in which high shock factors are experienced, this spring i3, has a vital major purpose, as follows:
A major disadvantage of the hitherto type of bearing is that when the plough discs 3l or 32 strike an 'obstacle or obstruction, and the jump arm is actuated, the disc rises to clear the said obstruction, and is then abruptly forced back into the earth by the power of the compressed jump-arm spring and the weight of the mechanism.
rates Patent Cil f1ice If the disc, on being abruptly forced into the earth in this manner, should strike a solid object, such as a rock, then invariably the hardened brittle cups or cones, fracture under the impact. This disadvantage has been overcome in the herein bearing, by installing the spiral spring l as aforesaid, and fitting for example, a lead-bronze washer i5 between the captive bearing cup Ztl and the retaining collar or shoulder 14. The result is that the lead-bronze washer sufficiently dampens the shock and prevents the fracture ofthe captive cup 2t) or cone 2.
When a hitherto bearing fitted with dual captive bearing races is used on a twin disc plough, should the leading disc as strike an obstruction, and subsequently be released therefrom as abovementioned the rear cup 23 or cone 33 invariably fractures owing to the excessive jarring vertical leverage action incurred. This major disadvantage has been completely eliminated by installing the spiral spring as 13 in the bearing as set out herein, which prevents the cup or cone from fracturing, by allowing the spring loaded bearing cup 23 to move forward, when the vertical pressure exceeds a predetermined critical figure. This buffer action effectively prevents the cup or cone from fracturing.
Should the rear disc 32 strike an obstruction and subsequently be released therefrom as aforementioned, then the initial vertical shock is absorbed by the spring loaded cup 23, moving forward when the aforesaid vertical pressure exceeds a predetermined figure. Similarly, the jarring vertical leverage force operating in the opposite direction on the captive bearing cup 20 causes the leading cone 21 and roller l2, to move forward thereby compressing the spiral spring 13, which acts as a buffer, and thereby prevents the fracture of the captive bearing cup 2li, or the loading cone 2l.
It will be understood, of course that the main shaft 24, must move a fraction to the right, to enable the captive roller l2 held by the cone 21 to move forward on the captive cup 20. It is therefore, imperative that the spiral spring i3 be compressed and exerts an horizontal force powerful enough to enable the bearing races to operate eiciently and safely, but capable of being further compressed when vertical forces on the bearing cups exceed a predetermined figure. it has been found that a load of eighty-four pounds (84) compression on the spiral spring is the correct loading.
The'arrangernent shown in the drawings for absorbing radial shocks may be modified and yet still produce the same function. For instance, the tapered roller bearing ll may be replaced by a convention dual captive roller or ball race since the conversion of radial shocks to axial displacement of the shaft is mainly achieved through the action of the tapered roller bearing l2.
As shown in Fig. 3 companion ball races as 35, having therein balls as 39 may be employed in lieu of the rollers as aforesaid. One of these races as 35-39 is subjected to pressure from the spring i3, whilst its companion is held captive by the aforesaid collar or shoulder 14.
The races and therein balls, held captive by the shoulder i4 is not shown in this figure.
Each of these ball races is made with an angular contact lead-olf as 44;, for purposes hereinafter described.
The operation and action of these ball races, as applied A to the herein bearing, is similar to that described as afore- `'bursting of the bearing.
v .5 balls the scope and tendance for what may be termed a rolling relief.
Similarly, the vertical stress on the discv 31, exceeding Va predetermined critical figure, causesthe inner race to move inwardly', compressing thespiral spring 13, which absorbs the shock, thereby preventing fracture of the ballyrace held captive by the aforesaid collar 14, relief being likewise-imparted thereto by the rolling relief of the balls down the angular contact lead1 olf as aforesaid.
In this case also, the main shaft 24 must move longitudinally afraction to assist the spiral spring 13 to compress, therefore, a safety shoulder 41 is incorporated within the casing which prevents damage to the bearing as a whole, and also provides a safety factor in the event of breakage of the said spiral spring 13.
It has been `found `during experimental practice that a correct loading on the spiral spring in this instance is 120 pounds, but of course such loading is not arbitrary,
and may be varied to suit varying conditions.
Further, I have found that an excellent working angle .for the load-off contact 44 for the respective races is twelve and ahalf degrees U21/2) but it is to bel understood that I do not desire to limit myself to such angle, as various types of Vmachines working under differing conditions 4will need to vary such angular contact lead-olf.
Within the body of the ,main casing 10, and at each end thereof is also housed suitable sealing washers 16,'
either of a flat, cupped or other approved formation as desired, but it is essential that a high performance doublesidedleather and/ or rubber or other approved compound seal Vbe installed, ensuring the retention of grease under pressure, and the total exclusion of air and foreign matter.
The end plates 17 and 1S lof the bearing housing are made` with sand shrouds and grease grooves-19, and before being fitted into operative position, are packed with heavyV anti-friction grease to seal same against entry of sand and other foreign matter, tothe body of the casing.
The saidmain casing 10 of the bearing is also .provided with a grease nipple` 22 for the convenience of allowing a periodic re-filling with lubricant, and/ or when the pressure within the body of the casing falls below a predeter-V mined pressure for that necessary for eicient operation.
The variable pressure valve may for example comprise spring 28; "The extentof spring pressure maintaining the ball or unit 27 `on its seat is capable of being regulated by means of a screw-threaded cap 29, the said spring being held captive by cup washer 36.
When the bearing is. charged and filled withl grease or oil, any further supply at an enhanced pressure beyond 'that which has been predetermined, results in the valve opening, and the excess lubricant escaping through the p passages 39-'4-6 of the casing and valve respectively, raising the ball or unit as 27 against the spring 28, and'issuing through the outlet 47.
predetermined figure, oxidation and channelling is prevented, and the hitherto resultant frictional drag .in the bearing is entirely eliminated.
When this invention is used under sub-zero or cold conditions, it may be found desirable to increase the spring pressure of the said variable pressurevalve.
I have found that unsurpassing eiciency is attained if a lithium based light grease is used in this invention.
While I have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.
l. In combination, a bearing housing, a shaft extending axially through said housing, a iirst'anti-friction element fixed to said shaft and disposed within said housing, said housing forming an abutment surface therewithin, resilient means disposed in said housing and engaging said .Y V'al/body 26 and a ball or other appropriately shaped unit 27, closeable against its seat 35, under the inuence of a When such bearing is used in the normal Way, the expension of the lubricant, through heating or otherwise, increases the pressure withinV the bearing casing, and thus opens the valve and allows the escape of a sucient Vamount of'lubricant, to restore the normal predeter-Y mined pressure therein. In consequence, the seals do not K break. under pressure, and there is no possibility of `a ever, experiments have proved that, in a moderate climate,
an internal operating pressure of 5 to 8 pounds per square inch is the most e'icient operating pressure; consequently the temperature of the lubricant does not rise j beyond a abutment surface and said rst anti-friction element, Vrespectively, to cushion axial displacement of said first antifriction element, and a second anti-friction element having sections relatively displaceable axially when subjected to radial shocks ydisposed in the housing with one of said displaceablev sections fixed to said shaft, whereby said shaft is axially displaced against the tension of said resilient'means when said shaft is subjected .to a radial shock.
2. The combination, as setforth in claim 1, wherein said abutment surface is formed as an annular shoulder projecting substantially radially inwardly from the inner face of said housing and which includes a shoclrabsorbing washer disposed between said annular shoulder and said second anti-friction element. n
3. The combination, as set forth in claim, 2, in which said `shock absorbing washeris of a lead-bronze composition.l
4. In combination, a bearinghousing, a shaft extending axiallythrough said housing, an annular shoulder projecting substantially radially inwardlyfrom the inner face of said housing, a first anti-friction element xed ,to said shaft and disposed within said housing, resilient means disposed in said housing and engagingsaidannular shoulder and said rst anti-friction element, respectively, to cushion axial displacementof said first antifriction element, a second anti-friction elementhaving sections relatively displaceable axially when subjected to radial shocks disposed in said housing with one Vof its displaceable sections fixed to said shaft whereby said shaft is axially displaced against the tension of said resilientimeanswhen said shaft is subjected to a radial shock, said housing having a passage communicating with the interior thereof, and a variable pressure relief valve at the'outer end of said passage in order to maintain a predetermined pressure in said housing.
5. The combination, as set forthin claim 1, wherein said second anti-friction element is a tapered roller bear- 6. The combination, as set forth in claim 1, Vwherein said second anti-friction element isa ball bearing having balls interposed between opposing races and said races haveran angular contrast lead-olf, to impart rolling relief movement to said balls when subjected to stress. I
7,.V In combination, a bearing housing, a shaft extend" ing axially throughsaid housing, an annular shoulder projecting substantially radially inwardly from the inner face of said housing, a pair ofl anti-friction elements having sections relatively displaceable axially in response to radial shocks disposed within said housing with one section of each of said elements iixed to Vsaid shaft, a helical [spring disposed in said housing and engaging said annular shoulder and one of said anti-friction elements, respectively, to cushion axial displacement of said one antifriction element. f
8. The combination, as set forth in claim 7, wherein said housing comprises a main body having end faces,
and end plates engaging and complementary to said end faces of said main body.
9. The combination, as set forth in claim 8, wherein said end plates have axially extending projections overlapping the outer face of said housing to operate as sand shrouds.
10. The combination, as set forth in claim 8, wherein said end plates have axially extending inner cylindrical having peripheral grease grooves.
UNITED STATES PATENTS Dickson June 3, Cong July 13, Russell Sept. 7, Wood Dec. 27, Wightman Apr. 10, Birdwell Jan. 1, Shelden et al. Sept. 9, Kalikow Sept. 23,